The cafe's manager appeared unsure how to react. At one point it looked as though he was going to lock everyone inside. A small group of police officers went in and after half an hour the protesters left - peacefully but noisily - to join another group at a second Starbucks nearby.

As far as UK Uncut are concerned, Starbucks' offer to pay £20m is a marketing stunt. Many passing Christmas shoppers we've spoken to seem to agree that the law needs to be changed to force multinationals to pay more tax in the UK.

Rosie Rogers from UK Uncut told BBC News "We're absolutely delighted with the events... Hundreds of people turned out on a cold Saturday morning to exercise their right to protest."

Ms Rogers said there were no immediate plans to hold any similar demonstrations but they would continue to boycott Starbucks.

UK Uncut said it had heard from protesters gathering at 10 outlets in London, Birmingham, Oxford and Nottingham.

But employees from two Starbucks cafes in Birmingham who spoke to the BBC said just one person had turned up to hand out leaflets but had been asked to leave.

On Thursday, Starbucks revealed it would pay "a significant amount of tax during 2013 and 2014 regardless of whether the company is profitable during these years".

In a statement issued ahead of the protests, a Starbucks spokesperson said it had offered to meet with UK Uncut to discuss their concerns.

It added the company had "listened to our customers" and was "making a number of changes in our business to ensure we pay corporation tax in the UK" - something it urged UK Uncut and other concerned parties to "carefully consider".

By Robert PestonBusiness editor

Companies perceived by people, politicians and media as, in some sense, not making a proper contribution to the societies from which they extract their revenues and profits, will over time become marginalised within those societies

Starbucks has paid £8.6m in corporation tax in its 14 years of trading in the UK, and nothing in the last three years. The company had UK sales of nearly £400m in 2011 but has reported a taxable profit only once in its 15 years of operating in the UK.

Starbucks now says it expects to pay around £10m in corporation tax for each of the next two years, a move described by tax experts as unprecedented.

Speaking to BBC Radio 4's Today programme, Exchequer Secretary to the Treasury David Gauke said: "If a taxpayer wants to pay more than is required under the law then that is really a matter for them. It's a voluntary donation really rather than tax."

Other global firms such as Amazon and Google have also come under fire for avoiding paying tax on British profits.